In the inventory, some variables are used to manage the RT (see Cluster installation section).

Interrupt Requests

irqbalance is a daemon for SMP (Symmetric shared-memory multiprocessing) systems to help balance the CPU load generated by interrupts across all of a systems CPUs. irqbalance identifies the highest volume interrupt sources, and isolates each of them to a single unique cpu, so that load is spread as much as possible over an entire processor set, while minimizing cache miss rates for irq handlers.

The irqmask define the environment variable IRQBALANCE_BANNED_CPUS. It sould ignore some CPU and never assign interrupts (more details here, the irqbalance manual).

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